In a machine for inserting mail into envelopes, it is conventional for envelope advance means to bring successive envelopes to be filled into a defined filling position and to present them facing a mail path. Each item of mail is advanced along its path and then inserted into the envelope then waiting in the filling position. After being filled, the envelope in question is ejected.
While an envelope is advancing towards its filling position, the envelope flap is unfolded. The envelope as put into its filling position has its flap held unfolded so as to avoid interferring with the operation of inserting mail into the envelope.
In order to facilitate this insertion operation, envelope body opening fingers which are normally retracted ahead of the envelope in its filling position are actuated to take up an opening position in which they penetrate partially into the envelope body in order to open it prior to an item of mail being inserted therein.
These fingers are generally mounted at the end of an actuator arm which is controlled synchronously with the running of an insertion cycle in order to retract the finger and in order to put them into the opening position.
It is often not easy to mount such opening fingers and their control mechanism given the small amount of room which is made available for them since the overall side of the insertion machine should be kept as small as possible.
The object of the present invention is to provide a device for opening the body of an envelope to be filled, which device is very simple in design and is very easy to mount in an insertion machine, while nevertheless taking up very little room together with its control mechanism.